Select outlet
What is it?
Watershed shape depends on the location of the outlet/outlets. Users can select single or multiple outlets. SwaNET allows users to use default outlet, upload a outlet shapefile, or click on the stream network to create outlets.How to use it:
Use default outlet
When users select this option, the point in the stream network that has the largest drainage area is automatically selected as an outlet. This is the default option.Use USGS stations
This option allows users to add USGS sensor data stations as outlets. To use this option, users must have downloaded USGS sensor data.
If no data has been downloaded, exit SWAT pages and go to the main menu. Select Analysis Tools-->Data Explorer-->USGS Sensor Data. Draw a box in the SWAT model area and Click Conceptual Model Tools-->Save Shape. Follow the menu to download data.
Once the data is downloaded, select 'Use USGS stations'. If you have not selected model area, you may be asked to draw model area. Click 'Draw Shape' and draw an area around the SWAT model area. Once done, click 'Save Shape'. Click 'Load Stations'. USGS stations within the selected area are displayed as markers.
To add all the USGS stations as outlets, click 'Add all'. All the stations are added to the list under 'Outlets'. To delete selected outlet, select an outlet and click 'Delete'. To delete all USGS outlets, click 'Clear'.
To view data availability, click any marker. A new pop up window with site name, number of field observation data points, start date, end date and link to USGS site appears.
To view the field measurement data, click 'View Field data'.
To download and view daily data, click 'View daily data'. This option downloads daily data from USGS station in real time, and plots it.
To add the USGS station as an outlet, click 'Create outlet'. The station is added to the list.
Once all the desired outlets have been added, select 'Snap threshold'. If any outlet is within the threshold value, the USGS stations are snapped to the nearest stream. To add the outlets to any previously snapped outlets, check 'Add to existing'. Click 'Snap outlets'. Outlets are snapped to the nearest streams and the number of snapped outlets are displayed.
Upload outlet shapefile
If users have a outlet shapefile, users can upload it and use it. Keep in mind that while uploading user outlet, the outlet points must lie on the stream network. Otherwise, the watershed will be empty.To use an outlet file already uploaded to the server, click "Use Uploaded File". A list of already uploaded files appear. Click on the desired file name.
To upload a new outlet file, check the box next to 'Import' and click 'Import'. Browse to the desired outlet file.
Draw outlets
Draw outlet option allows users to directly click on the map to create outlets. Users can create single or multiple outlets.To add an outlet, click 'Add outlet' button and click on the map. Repeat this process to add other outlets.
To remove an outlet, click the outlet in the outlet list and click 'Delete outlet'.
Once the outlets are places, define snapping threshold. If the distance between streams and outlet is greater than snapping threshold, the outlet is not placed. So, make sure to zoom close to the stream network before placing outlets. To add to existing outlets, check 'Add to existing'. Click 'Snap outlet'. The outlets are snapped to the stream network.
Create watershed
After outlet option is done, click 'Create watershed'.A watershed map with stream network and subbasin number is displayed.
Merge subbasins
Merging subbasin is optional. If you don't want to merge any subbasin, click 'Finalize watershed'.To merge smaller subbasins to their parent subbasins, click 'Merge subbasins'. The menu expands.
Select subbasin number on the left side and click 'Select subbasin'. The subbasin is added to the list on the right. Once all the subbasins to merge are added, click 'Merge subbasins'. This process can be done multiple times.